Lens profiling tool from Adobe ( for CS5 / LR / ACR ).

"nospam" wrote in message
...
In article , Mxsmanic
wrote:

Profiling lenses is doing things backwards.

actually it isn't backwards at all.

The computing power should be spent on making better lenses, not trying
to
remove lens defects after the fact.

it's both.

Why have millions of PCs trying to undo
lens defects when a single computer could simply design a better lens
instead?

because nothing is perfect. fixing some of the lens problems in
post-processing lets the designers concentrate on the more serious
aberrations that need to be dealt with in the lens itself.

Why not use a coke bottle bottom for a lens, put the distortion parameters
in Photoshop, and let the computer fix everything up?

Of course, I exaggerate, but the principal is basically good.....I took a
badly distorted photo of a building in Portland by not bringing my offset
lens along....I had to take it with a standard lens, and the building was
all skewed.....With Photoshop I was able to crank out the distortion and fix
it up so it looked like I had taken it with my offset lens. Since almost all
pics are taken with digital equipment, it occurred to me that these offset
lenses are really obsolete.....The anti distortion software could be built
right into the camera. In time, virtually all aberrations peculiar to lenses
could be solved in software, and built into the cameras, couldn't they?

In article , Bill Graham
wrote:

Why not use a coke bottle bottom for a lens, put the distortion parameters
in Photoshop, and let the computer fix everything up?

because it's impossible?

Of course, I exaggerate, but the principal is basically good.....I took a
badly distorted photo of a building in Portland by not bringing my offset
lens along....I had to take it with a standard lens, and the building was
all skewed.....With Photoshop I was able to crank out the distortion and fix
it up so it looked like I had taken it with my offset lens. Since almost all
pics are taken with digital equipment, it occurred to me that these offset
lenses are really obsolete.....

tilt shift lenses are not obsolete. there are situations where you need
it and *can't* fix it in post.

The anti distortion software could be built
right into the camera. In time,

it already is in some cameras.

virtually all aberrations peculiar to lenses
could be solved in software, and built into the cameras, couldn't they?

not all, and some are much better done in the lens.

"nospam" wrote in message
...
In article , Bill Graham
wrote:

Why not use a coke bottle bottom for a lens, put the distortion
parameters
in Photoshop, and let the computer fix everything up?

because it's impossible?

Of course, I exaggerate, but the principal is basically good.....I took a
badly distorted photo of a building in Portland by not bringing my offset
lens along....I had to take it with a standard lens, and the building was
all skewed.....With Photoshop I was able to crank out the distortion and
fix
it up so it looked like I had taken it with my offset lens. Since almost
all
pics are taken with digital equipment, it occurred to me that these
offset
lenses are really obsolete.....

tilt shift lenses are not obsolete. there are situations where you need
it and *can't* fix it in post.

The anti distortion software could be built
right into the camera. In time,

it already is in some cameras.

virtually all aberrations peculiar to lenses
could be solved in software, and built into the cameras, couldn't they?

not all, and some are much better done in the lens.

This may well be true today, but in time I believe "all" will be the correct
term.....After all, we are talking about reducing a photograph to millions
of individual pixels, each one being several digital bytes that can be
changed by the right software....there is no reason to suspect that sometime
in the future, the proper combination for every byte will be known, and be
able to be corrected, right on the spot.

On 5/11/2010 11:13 PM, nospam wrote:
In article3r6dnWR7k8tLhHfWnZ2dnUVZ_g2dnZ2d@giganews. com, Bill Graham
wrote:

Why not use a coke bottle bottom for a lens, put the distortion parameters
in Photoshop, and let the computer fix everything up?

because it's impossible?

Maybe not. Given a thorough enough analysis of the transfer function it
has been shown that an image can be recovered after passing through a
sheet of paper. Not much point to it though when it's easy to make far
better lenses than a coke bottle bottom.

Of course, I exaggerate, but the principal is basically good.....I took a
badly distorted photo of a building in Portland by not bringing my offset
lens along....I had to take it with a standard lens, and the building was
all skewed.....With Photoshop I was able to crank out the distortion and fix
it up so it looked like I had taken it with my offset lens. Since almost all
pics are taken with digital equipment, it occurred to me that these offset
lenses are really obsolete.....

tilt shift lenses are not obsolete. there are situations where you need
it and *can't* fix it in post.

The anti distortion software could be built
right into the camera. In time,

it already is in some cameras.

virtually all aberrations peculiar to lenses
could be solved in software, and built into the cameras, couldn't they?

not all, and some are much better done in the lens.

The thing that preacherman doesn't get is that we don't know how to make
a perfect lens--they're all compromises to some extent--the question is
what you trade to get what.

In article , J. Clarke
wrote:

The thing that preacherman doesn't get is that we don't know how to make
a perfect lens--they're all compromises to some extent--the question is
what you trade to get what.

exactly, and fixing some things on a computer is a better choice than
in the lens. it's the end result that matters.

"nospam" wrote in message
...
In article , J. Clarke
wrote:

The thing that preacherman doesn't get is that we don't know how to make
a perfect lens--they're all compromises to some extent--the question is
what you trade to get what.

exactly, and fixing some things on a computer is a better choice than
in the lens. it's the end result that matters.

Well, there is no question that the information must be captured somehow
before you can correct it and display it on a photograph, but it seems to me
that if it does exist, cleaning it up in software would be a better way to
go than trying to do it in the lens.....Especially when good lenses can cost
more than the cameras they are hanging on, and are pretty heavy, too. I was
very impressed with Photoshop's ability to correct my building photo.....I
look forward to a bright future from the software people....:^)

"Mxsmanic" wrote in message
...
nospam writes:

exactly, and fixing some things on a computer is a better choice than
in the lens. it's the end result that matters.

No, it is always better to correct as early in the process as possible, so
that you lose a minimum of information.

In real life, you can't correct "early in the process". Real lenses have
tradeoffs that you have to live with, and after-the-fact correction makes it
much easier to deal with.

If you have a choice between a sharp lens with distortion (Zeiss 21/2.8) and
a soft lens without (Sigma 12-24), you shoot the sharp lens and fix the
distortion. (Unless you need the extreme focal lengths and have to put up
with soft.)

--
David J. Littleboy
Tokyo, Japan

In article , Mxsmanic
wrote:

exactly, and fixing some things on a computer is a better choice than
in the lens. it's the end result that matters.

No, it is always better to correct as early in the process as possible, so
that you lose a minimum of information.

in an ideal world yes, however, you can't fix *all* of the problems in
a lens and if you want to design something that can be manufactured for
a reasonable price and perform well, you need to make some tradeoffs.

for instance, barrel distortion on a wide angle lens is easier to fix
on a computer, rather than adding more elements (potentially increasing
flare) and maybe ending up with weird moustache distortion instead,
which in my opinion, looks worse.

On 12/05/2010 5:41 p.m., nospam wrote:
In , Mxsmanic
wrote:

exactly, and fixing some things on a computer is a better choice than
in the lens. it's the end result that matters.

No, it is always better to correct as early in the process as possible, so
that you lose a minimum of information.

in an ideal world yes, however, you can't fix *all* of the problems in
a lens and if you want to design something that can be manufactured for
a reasonable price and perform well, you need to make some tradeoffs.

for instance, barrel distortion on a wide angle lens is easier to fix
on a computer, rather than adding more elements (potentially increasing
flare) and maybe ending up with weird moustache distortion instead,
which in my opinion, looks worse.

I think that "moustache" pattern distortion is a feature of zooms using
aspheric elements (and probably particularly "hybrid" aspherics) to
correct barrel distortion.
PTLens fixes it - does the PS CS5 plugin?
It's also usually only pronounced at extreme zoom range. Some of the
zooms I've used have it - and get severely lambasted in some reviews
because of it. OTOH a couple of points :
*most of these lenses have sweet spots, where distortion is even less
than typical primes of the same focal length.
*if the lenses were made identically, but with the last couple of mm
focal length shaved from the extreme, the same reviewers who lambaste
them would probably rave about how great the lens is.
*sometimes it (distortion) matters, often it doesn't. A good
photographer (at least one with limited resources) should learn the
characteristics of their gear, what can be corrected in PP, and shoot
accordingly.

In article , Me
wrote:

I think that "moustache" pattern distortion is a feature of zooms using
aspheric elements (and probably particularly "hybrid" aspherics) to
correct barrel distortion.
PTLens fixes it - does the PS CS5 plugin?

yes